Fossils/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby Moby digs a very deep hole and finds a bone. MOBY: Beep. Moby goes over to Tim who is reading a book. TIM: You found a fossil? Moby shows Tim the bone. TIM: Hey, why are you digging a hole in the backyard? MOBY: Beep. TIM: I don't think that's a fossil. I think it belongs to the Rottweiler next door. A dog barks. Tim reads from a typed letter. TIM: Dear Tim and Moby, What makes something a fossil? From, Ross. Well, a fossil is a remnant of an organism. An image shows many different fossils. TIM: Usually, fossils are at least several thousand years old and found in the ground. Not every organism gets fossilized after it dies. As a matter of fact, it's a pretty rare occurrence. Fossilization has to start off with the right circumstances, like a quick burial. An image shows a liquid sap falling on a bug, and the sap turning solid. TIM: This is a body fossil; a part of the original organism that's been preserved. It's a bug that got trapped in amber, a type of sticky tree sap. Over time, the sap hardened and we were left with this little keepsake. Body fossils are usually found in places where bacteria, insects, and the other things that cause decay aren't able to thrive. Images show an Eohippus in a desert, a Wooly Mammoth in a snowstorm, a bug in sap, and a saber-toothed tiger in a tar pit, all transforming into fossils. TIM: They form when an animal dies in the desert, or gets frozen in ice, or, I don't know, gets trapped in a tar pit. MOBY: Beep. TIM:Yeah, well, body fossils are really rare. An image shows a dinosaur print in stone. TIM: Trace fossils, like these footprints, are the most common fossil type. Trace fossils can include animal tracks, nests, bite marks, even animal poop. An animation shows a shelled organism dying and falling to the bottom of the lake where it is immediately buried in sand and slowly turning into rock. ] TIM: Other types of fossils form when an animal dies and is immediately covered by earth, mud, or sand. The covering slows decay down to a crawl and eventually turns to solid rock. The hardest parts of the animal; stuff like bones, teeth, and shells; don't decay for thousands of years. An animation shows the shell imprinted on the rock. TIM: When they finally do, they've left a lasting impression in the rock. That's a mold fossil: a hollow print. An animation shows the shell changing into a mold fossil. TIM: Sometimes, water will bubble up through the earth, filling a mold with minerals. Over time, the minerals harden into rock, leaving a cast fossil. An animation shows a cast fossil next to the original shell. TIM: A cast fossil looks just like the original bone or shell. MOBY: Beep. TIM: Right, of course, there are also carbon-based fossil fuels. An image shows black oil, a gas flame, and a piece of coal. TIM: All of the oil, gas, and coal on Earth was formed from the remains of fossilized plants and animals. An animation shows how fossils are formed from dead trees and plants in a swamp. TIM: For example, way, way, way back, like three-hundred million years ago, much of the planet was covered by tropical swamps. When the trees and plants that lived there died, they drifted to the bottom of the swamp. There, they slowly decomposed and formed a soggy, spongy substance called peat. Eventually, the peat got buried under layers of dirt and rock. Heat and pressure took their toll, and after millions of years, the peat turned into coal. Anyway, we can learn a lot from fossils. By looking closely at the fossil record, we can discover when and where lots of different organisms lived. An image shows two dinosaurs. TIM: In fact, we can learn about the entire history of life on Earth. MOBY: Beep. TIM: Oh, the fossil record is just a fancy term for the sum total of what we know about fossils. Moby holds a leaf. MOBY: Beep. Moby squeezes the leaf and makes a motor sound. TIM: Yeah, that's not gonna work. It has to be under extreme pressure for millions of— The leaf turns to coal. TIM: Huh. Category:BrainPOP Transcripts Category:BrainPOP Science Transcripts